1. Field of the Invention
The present invention pertains to apparatus for testing properties of materials. Specifically, it pertains to apparatus for testing the hardness properties of materials.
2. Brief Description of the Prior Art
It is frequently necessary to determine certain physical properties and characteristics of materials. This is particularly true in the production of metal goods where a particular range of properties such as hardness may be specified or required in the production thereof. Hardness, as generally applied to physical properties of materials such as metals, can be measured by determining resistance to penetration. Several scales or standards of reference for hardness of materials have been developed over the years. Two of the most common scales are the Rockwell and Brinell hardness scales.
Various testing methods have been developed to indicate or measure the hardness properties of materials. These hardness testing methods usually measure indentation or penetration of a penetrating device to which predetermined loads are applied. Commonly, the penetrating device, upon clamping of the material to be tested within the tester, is placed against the material with a minor or preliminary load. Then a full or major load is applied to the penetrator. The difference of penetration of the material between the minor and major load is measured, on a suitable indicator. This measurement then gives an indication of the hardness of the material.
With many testers of the prior art, it is necessary to bring the material being tested to the tester for clamping therein prior to the test. This is difficult with particular goods, such as pipe and rods. Furthermore, the clamping of certain goods, such as pipe collars, within testers may result in inaccurate readings due to the deformation of the tested goods, not from penetration but from distortion by the particular clamping mechanism or operation of elements of the testing apparatus.
Because of the problems associated with bringing certain goods, such as pipe, to a tester, mobile testing apparatus have been developed. Mobile testers are normally designed for clamping to the material to be tested without the necessity for a permanent or stationary work table. However, due to the varied and changing testing requirements, mobile testers do no exist which are totally acceptable for many situations, particularly testing the hardness of pipe collars.